How & Why We Use Pesticides

Posted on Wednesday, May 27, 2015 by Andrew

It may be among the more controversial practices around the farm, but spraying pesticides is an essential one. Why is it so essential? Well, as the sprayer heads out to get a head start on the spring weeds, let’s take a look.

A pesticide sprayer sits idle in the field, ready to help control the growing dandelion population.

A pesticide sprayer sits idle in the field, ready to help control the growing dandelion population.

Why spray pesticides in the first place?

Weeds in your flower beds can have the same effect as weeds in a field. They can rob a plant of sunlight, moisture and nutrients and have a negative impact on how the plant you actually want there – performs. For my flowerbed around the house, the stinkweed and thistle can quickly take control of my favourite hostas and irises. It is why this time of year we are also making the rounds around the flower beds, pulling weeds. The challenge in the field is instead of a few 10 square foot flower beds, we have hundreds of acres to keep the weeds down. We simply don’t have the ability to take a hoe and trowel to the field and pull each one individually and repeatedly. That’s where pesticides come in. By spraying a particular product, you can cover a field in a short amount of time and kill out almost all of the weeds. That will mean a strong start for the little corn, soybean, oat and alfalfa plants that will soon be poking out of the ground.

But organic farms can do it without pesticides, why can’t you?

A great question I see a lot. The reality is most organic farms actually do use pesticides as well, they are just a different kind of pesticide. Many of the ones we use are considered synthetic, or man-made. Most of the pesticides an organic farmer will use are considered natural. One is not safer than the other, they are simply different. It is important to remember though that simply saying synthetic is bad and natural is good doesn’t bring into account the advances we’ve made in technology, medicine and now agriculture – thanks to researchers working to solve some big challenges.

How often do you spray a pesticide?

The short answer is: that depends. We only want to spray when necessary, so do it as little as we can. Most of our fields will get sprayed at least once to help control weeds with a herbicide. Beyond that, certain crops may or may not require a fungicide to help fight disease and others may or may not require an insecticide to control crop eating insects. Those products are only used on particular crops when needed, so we always hope we don’t have to.

How much pesticide are you actually using?

Every pesticide has a different rate of application. These are guidelines that are recommended in order to make sure the least about of pesticide is applied, but has the best impact. For instance, the common herbicide glyphosate has a guideline of 0.67 litres per acre. That’s equal to one drop for every five square feet.

Farmers using pesticides need to be trained and pass a test in order to be able to purchase or apply the product, so they are fully aware of how to follow the given guidelines and know how to properly use them.

Is there other things you can do beside spraying pesticides?

That depends again on the crop, time of year and what is threatening the growing grain. Some farmers use tillage tools like a cultivator to dig up some of those weeds. But, you may notice in your flowerbeds that just because you pull a weed, doesn’t mean you get rid of it – and once the crop starts to grow, tillage becomes harder to do without doing damage to the grain plants. Depending on the insect, growing genetically-engineered crops can protect the plant without the need for more pesticides. But again, the type of crop and type of insect can all make that a case-by –case scenario, year by year.

I’m worried about pesticide residue though.

The good news, is you don’t need to worry. Every pesticide used has been tested and ‘harvest dates’ are created to ensure that the crop is not harvested for a set number of days after that spray is applied. Depending on the pesticide depends on the length of time. Sometimes it can be a few days. Other times it can be several weeks. And while we occasionally see pesticide residue number in the news or on ‘medical-expert’ shows, the University of California, Davis has done a great job at giving perspective beyond just a simple parts per million or parts per billion number that actually means very little. (You can click here to see that)

Hopefully that clears up some of the questions you may have around pesticides. In the meantime, the sprayer has wrapped up the latest field and soon the grain plants will start erupting from the soil – having the best opportunity they can to grow tall and strong. Unfortunately I don’t have a good herbicide for the flower beds, so I’ll head back to weeding them…by hand…for the 4th week in a row. Ugh. These hostas better look good.